The Justice Department’s special counsel announced a sweeping indictment Friday of a notorious Russian group of Internet trolls — charging 13 individuals and three companies with a long-running scheme to criminally interfere with the 2016 U.S. presidential election.

The Internet Research Agency, based in St. Petersburg, was named in the indictment as the hub of an ambitious effort to trick Americans online into following and promoting Russian-fed propaganda that pushed 2016 voters toward then-Republican candidate Donald Trump and away from Democratic rival Hillary Clinton.

The indictment charges that the Russian efforts began in 2014, when three of the Russian conspirators visited 10 states, gathering intelligence about U.S. politics. Officials say that as the operation progressed, the suspects also engaged in extensive online conversations with Americans who became unwitting tools of the Russian efforts. The indictment does not accuse the Russian government of involvement in the scheme, nor does it claim that it succeeded in swaying any votes.

Deputy Attorney General Rod J. Rosenstein said the suspects “allegedly conducted what they called ‘information warfare against the United States,’ with the stated goal of spread[ing] distrust towards the candidates and the political system in general.”

The suspects, Rosenstein said, “took extraordinary steps to make it appear that they were ordinary American political activists.”

On Twitter, President Trump declared that he was vindicated.

“Russia started their anti-US campaign in 2014, long before I announced that I would run for President,” he wrote. “The results of the election were not impacted. The Trump campaign did nothing wrong — no collusion!”

The 37-page indictment includes some startling accusations against the election trolls, including that when news broke in September that special counsel Robert S. Mueller III was investigating their activity, one of them wrote: “We had a slight crisis here at work: the FBI busted our activity (not a joke). So I got preoccupied with covering tracks together with the colleagues.” The person, named as Irina Viktorovna Kaverzina, allegedly added: “I created all these pictures and posts, and the Americans believed that it was written by their people.”

Such accusations suggest that Mueller’s investigators were able to penetrate deep into the ­internal communications of the St. Petersburg troll farm, but the indictment does not spell out how they gained such access.

Friday’s indictment provides the most exhaustive description to date of allegations about Russian interference in the election, describing an 80-person team with specialists in graphics, data analysis and search-engine optimization that set out to con Americans online.

At times, they paid people to engage in political theater, such as paying for the construction of “a cage large enough to hold an actress depicting Clinton in a prison uniform,” according to the charges. It is against U.S. law for non-Americans to make expenditures or disbursements in an effort to affect the outcome of a U.S. election.

'It is spooky'

Prosecutors said the Russians, using fake identities, contacted Trump campaign staffers in Florida offering to hold rallies to support Trump. Susie Wiles, who was co-chair of the Trump campaign in Florida in August 2016 and later became the campaign’s chief Florida staffer, said no campaign official was aware of the Russian effort.

“It’s not the way I do the business; it’s not the way the Trump campaign in Florida did business,” she said. “It is spooky. It is awful. It makes you look over your shoulder. It shouldn’t happen. I’m anxious for this to be uncovered so this never happens again.”

In Congress, politicians in both parties condemned the alleged Russian interference.

“We have known that Russians meddled in the election, but these indictments detail the extent of the subterfuge,” House Speaker Paul D. Ryan (R-Wis.) said in a statement. He accused the indicted Russians of “a sinister and systematic attack on our political system.”

“Today’s announcement underscores why we need to follow the facts and work to protect the integrity of future elections,” he added.

But that very task — taking steps to prevent future election meddling — has thus far stymied the leaders and committees on Capitol Hill investigating Russian actions. In the House, the parties are openly accusing one another of prioritizing political attacks over taking real steps to protect the country.

“Today’s indictments should lay to rest any assertions by President Trump that the special counsel’s investigation is a ‘hoax’ or a ‘witch hunt,’ ” said Rep. Jerrold Nadler (N.Y.), the top Democrat on the House Judiciary Committee. “At this point, any step President Trump may take to interfere with the special counsel’s investigation — including removing Deputy Attorney General Rosenstein or threatening to remove special counsel Mueller directly — will have to be seen as a direct attempt to aid the Russian government in attacking American democracy.”

Prosecutors said the Internet Research Agency kept a list of real Americans whom its employees had contacted using false personas and asked to assist the effort. The list, which numbered more than 100 people by late August 2016, included the U.S. citizens’ contact information, a summary of each person’s political views and the activities the Russians had asked them to undertake.

None of those charged are in custody, according to Peter Carr, a spokesman for the special counsel’s office. Russia does not allow its citizens to be extradited to the United States to face trial, so it is unlikely the individuals will be turned over, but the indictment probably will prevent them from traveling outside Russia.

Some of the Russians posed as Americans and, without revealing their Russian identities, “communicated with unwitting individuals associated with the Trump campaign and with other political activists to seek to coordinate political activities,” the indictment said.

By February 2016, the suspects had decided whom they were supporting in the race, according to the indictment, which quoted an instruction to Internet Research Agency specialists to “use any opportunity to criticize Hillary and the rest (except Sanders and Trump — we support them.)” Sen. Bernie Sanders of Vermont was running for the Democratic nomination.

Prosecutors say some Russian employees of the troll farm were chastised in September 2016 when they had a “low number of posts dedicated to criticizing Hillary Clinton” and were told it was “imperative to intensify criticizing” the Democratic nominee in future pieces.

Stolen identities

The charges include conspiracy to defraud the United States, conspiracy to commit wire fraud and bank fraud, and aggravated identity theft. Many of the charges center on the use of at least a half-dozen bank accounts to buy ads online or participate in political activism.

In a related move, prosecutors announced that a Santa Paula, Calif., man had pleaded guilty Monday in Washington to identity fraud, admitting that he made tens of thousands of dollars by creating hundreds of bank accounts, often using stolen identities. Richard Pinedo, 28, sold the accounts to unidentified offshore users, apparently including suspects connected to the Russia probe.

Prosecutors released documents unsealed Friday that showed that Pinedo was charged Feb. 7 after entering a plea deal five days earlier in which he agreed to cooperate with investigators in exchange for an advisory sentencing guideline of 12 to 18 months in prison.

Pinedo attorney Jeremy Lessem said his client “had absolutely no knowledge” of who his purchasers were or what they did with the information he sold, adding that to the extent his actions may have assisted anyone in interfering with the election, that “was done completely without his knowledge or understanding.”

One of those indicted Friday was Yevgeniy Viktorovich Prigozhin, a well-known figure that the Russian news media has identified as the financial backer of the Internet Research Agency. He is a caterer who has been nicknamed “Putin’s chef” because of his close ties to Russian President Vladi­mir Putin. Concord Management and Consulting and Concord Catering, two Russian businesses also charged by Mueller’s team Friday, previously have been identified as Prigozhin vehicles.

“The Americans are very impressionable people, and they see what they want to see,” Prigozhin told Russia’s RIA Novosti state news agency in response to the indictment. “I respect them very much.”

Referring to the list of indicted individuals, he added: “I am not at all disappointed that I appear in this list. If they want to see the devil — let them.”

The Internet Research Agency was at the center of Silicon Valley’s investigation into Russian meddling during the 2016 election. Facebook, Twitter, Instagram and Google all found evidence that the private firm used social media to divide American voters across a range of polarizing issues, including race, religion, gun rights and immigration.

A Twitter spokesman said: “Russian efforts to disrupt the 2016 U.S. election, in part by abusing social media platforms, go against everything we at Twitter believe. Any activity of this kind is intolerable, and we all must do more to prevent it.”

The Internet Research Agency is regarded as the most prominent part of the Russian disinformation campaign, although congressional investigators pushed for evidence of other operations, including from countries other than Russia, that shared the same purpose.

Anton Troianovski in Berlin and Craig Timberg, Spencer S. Hsu and Karoun Demirjian in Washington contributed to this report.